Jack



FIG. 1 is a side elevation view of a jack showing our new design.

FIG. 2 is a side elevation view thereof opposite to that shown in FIG. 1.

FIG. 3 is a front elevation view thereof.

FIG. 4 is a rear elevation view thereof.

FIG. 5 is a top plan view thereof.

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a jack, as shown. 